1. Field of the Invention
This invention relates generally to access devices and more specifically to seals and insufflation mechanisms applicable to such devices.
2. Discussion of the Prior Art
Access devices are commonly used in surgery to facilitate the introduction of various surgical instruments into vessels, conduits, cavities, and other interior regions of the body. These access devices include, for example, devices which facilitate the introduction of a needle into a vessel, and trocars which facilitate the introduction of laparoscopic instruments into the abdomen of the body.
Some of these access devices are introduced into regions which include a fluid under pressure. In the case of a needle access device, this fluid may be a liquid such as blood. In the case of a trocar, this fluid may be a gas such as an insufflation gas. In either case it is desirable to provide for the introduction of the surgical instrument into the cavity without permitting the escape of the pressurized fluid.
In the case of trocars, a cannula at the distal end of the trocar is typically connected to a seal housing at the proximal end of the trocar. Together the cannula and housing form a working channel through which various instruments can be inserted to access the cavity. Seal mechanisms are commonly disposed in the housing and include a septum valve which seals the working channel when an instrument is in place, and a zero closure valve which seals the working channel when the instrument is removed.
Maintenance of an insufflation pressure has been accomplished by various structures associated with the trocar. In one case, an insufflation inlet is provided directly into the cannula distally of the housing. A valve associated with this inlet can be opened and closed to control the insufflation pressure. These valves and inlets have been particularly troublesome when incorporated into reusable trocars, where the intricacy of these structures has made them difficult to clean and sterilize for repeated use.